The mitochondrial fraction of rat liver homogenate catalyzed the conversion of cholesterol into 5-cholestene-3P,25diol and 5-cholestene-30,26-diol in the presence of an NADPH-generating system and oxygen. 5-Cholestene3P,26-diol was the predominant product. 26-Hydroxylation of cholesterol was much more efficient with the NADPHgenerating system than with NADPH alone, and it was shown that the iso...

The inhibition and mechanism-based inactivation potencies of irinotecan (7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin; CPT-11) and its active metabolite (7-ethyl-10-hydroxycamptothecin; SN-38) for human cytochrome P450 (P450) enzymes were investigated to evaluate the potential for drug interactions involving CPT-11 using microsomes from insect cells expressing specific huma...

Magnolin, epimagnolin A, dimethyllirioresinol, eudesmin, and fargesin are pharmacologically active tetrahydrofurofuranoid lignans found in Flos Magnoliae. The inhibitory potentials of dimethyllirioresinol, epimagnolin A, eudesmin, fargesin, and magnolin on eight major human cytochrome P450 (CYP) enzyme activities in human liver microsomes were evaluated using liquid chromatography-tandem mass s...

A constitutive cytochrome P-450 catalyzing 25-hydroxylation of C27-steroids and vitamin D3 was purified from rat liver microsomes. The enzyme fraction contained 16 nmol of cytochrome P-450/mg of protein and showed only one protein band with a minimum molecular weight of 51,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified cytochrome P-450 catalyzed 25-hydroxylatio...

1. The metabolism of 4-[4-14C]androstene-3,17-dione, 4-[4-14C]pregnene-3,20-dione, 5a-[4-14C]androstane-3a,17f8-diol, [4-4C]cholesterol, 7a-hydroxy4-6fi-3H]cholesten3-one, 5fi-[7fi-3H]cholestane-3a,7U-diol and [3H]lithocholic acid was studied in the microsomal fraction of livers from control and orotic acid-treated male rats. 2. As a result of the treatment the orotic acid-fed rats had fatty li...

Microbial transformation has been successfully applied in the production of steroid intermediates with therapeutic use and commercial value in pharmaceutical industry due to its high regio- and stereo-selectivity. As such, it is still important to screen microbial strains with novel activity or more efficient abilities in the development of the commercial steroid industry. Biotransformation of ...

Cytochrome P450 BM-3 from Bacillus megaterium catalyzed NADPH-supported indole hydroxylation under alkaline conditions with homotropic cooperativity toward indole. The activity was also found with the support of H2O2, tert-butyl hydroperoxide (tBuOOH), or cumene hydroperoxide (CuOOH). Enhanced activity and heterotropic cooperativity were observed in CuOOH-supported hydroxylation, and both the H...

Hydroxylation of steroids in V&O at carbon atom 21 by adrenal tissue preparations has previously been reported by Plager and Samuels (l), Hayano and Dorfman (2), and the present authors (3). The former workers described a system consisting of a 20,000 X Q supernatant fraction of beef adrenals which effected hydroxylation in this position of progesterone and ita derivatives in the presence of ad...

The aim of the present study was to identify the metabolites of the new designer drug alpha-pyrrolidinovalerophenone (PVP) in rat urine using GC/MS techniques. Eleven metabolites of PVP could be identified suggesting the following metabolic steps: hydroxylation of the side chain followed by dehydrogenation to the corresponding ketone; hydroxylation of the 2''-position of the pyrrolidine ring fo...

Prolyl hydroxylation is a critical posttranslational modification that affects structure, function, and turnover of target proteins. Prolyl 3-hydroxylation occurs at only one position in the triple-helical domain of fibrillar collagen chains, and its biological significance is unknown. CRTAP shares homology with a family of putative prolyl 3-hydroxylases (P3Hs), but it does not contain their co...